Installation and Operating Instructions - Crompton Instruments

Parameter details
Range of Current Trip point
5 — 120% of nominal input
Range of Rated Voltage Trip point 80 — 120% of nominal input
Range of Time-Current Characteristic Curves (Time Curve)
1 Standard Inverse
2 Very Inverse
3 Extremely Inverse
Time Dial Setting Range 0.1 to 9.9
Time Dial Setting Resolution 0.1
Resolution of curve timebase
100 milliseconds
Accuracy of timing (relative to the ± 5% of ideal + 2 loop times
characteristics described below)
Maximum Input current for which 25 Amps for 5 Amp nominal unit
Time-Current characteristics are valid 5 Amps for 1 Amp nominal unit
TYPE 51G — TIME OVER CURRENT NEUTRAL GROUND FAULT CHECK
Brief details
This trip has different implementations on models SPR-013 and SPR-014, as follows:
SPR-014 (3 phase 4-wire systems with neutral CT): The fault current is calculated as the
difference between the vector sum of the three phase current inputs and the neutral current
input.
SPR-013 (3 phase 3-wire systems): The fault current is the vector sum of the three phase current
inputs only. Do not connect any signal to the Neutral current input terminals.
IMPORTANT: Ground fault current is not directly measured. This parameter is derived
by calculation. This unit has not been tested to UL 1053. The trip function is intended
for monitoring purposes only.
Parameters
You must specify the following parameters for operation of the neutral ground fault relay:
●
The maximum permitted value of the RMS of the vector sum of phase current inputs
and the neutral current input from the “generator”.
●
The “Time Dial Setting”.
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